Due to the decreasing size of memory elements their susceptibility to value corruption due to radiation induced effects from cosmic radiation is becoming a noticeable problem in some critical applications. Even within these applications, some memory uses are more vulnerable than others. Errors to the operating program can be very serious as they can lead to indefinite malfunctioning of the equipment. Such errors often require the device to be reset. Other errors in the data memory are considerably less dangerous for some applications because there is often some ambiguity as to the data anyway. In these cases the soft-error only causes a marginal increase in this ambiguity. This may be undetectable. This invention is a method for protecting the critical program memory for these types of applications. This invention also gives some limited protection to other memory uses like constant data.
Traditionally memories are protected by generating a number of parallel bits based on Hamming codes on a one-dimensional array of data bits often referred to as a memory line. This invention is a method of reducing the overhead of protecting memory from the rare radiation induced memory events. This invention employs just one bit of traditional parallel generated parity per memory line and a second serially generated parity bit per location in the memory line.